New York: Yahoo Inc has threatened action against Facebook if the social networking giant does not pay licence fee for using technologies which the Internet search major claimed come under its intellectual property rights.

"We must insist that Facebook either enter into a licensing agreement or we will be compelled to move forward unilaterally to protect our rights," Yahoo said in a statement.

Yahoo, however, did not disclose which are the specific technologies, for which Facebook should pay.

The New York Times had earlier reported that Yahoo is forcing Facebook to license 10 to 20 patents over technologies that include advertising, personalisation of websites, social networking, and messaging.

"Yahoo has a responsibility to its shareholders, employees and other stakeholders to protect its intellectual property. We have invested substantial resources into these innovations. Recognising that, other major web and technology companies have already licensed some of these technologies," Yahoo said.

Meanwhile, Facebook in a statement has reportedly said that "Yahoo contacted us at the same time they called The New York Times and so we haven't had the opportunity to fully evaluate their claims."

Yahoo owns more than 1,000 patents.

Interestingly, Yahoo's revenue has been steadily falling during the past three years, while Facebook's revenue has witnessed a significant surge.